In a conventional forming apparatus, for example, with a two-component developing unit in which the developing unit that visualizes an electrostatic latent image formed on, for example, an image carrier, uses a toner including a toner and a carrier, since the toner is consumed with the formation of an image, it is necessary to sequentially supply the toner by the consumed amount. Therefore, in the image forming apparatus, a toner container storing the toner is provided, to supply the toner by the consumed amount from the container to the developing unit.
As the supply method of the toner from the toner container such as a toner bottle or a toner cartridge to the developing unit, a mechanical auger unit is heretofore mainly used. The toner transfer by the auger unit can control the transfer amount of the toner, but the transfer route is substantially limited to a linear route, and when the transfer route is long, coagulation of the toner may occur, thereby deteriorating the toner quality. Therefore, in the apparatus in which the toner transfer is carried out by the auger unit, the toner container should be arranged near the developing unit. Further, with the auger unit, even if the transfer distance is short, the toner cannot be raised at an acute angle. Therefore, the toner container must be arranged above the developing unit.
Patent Literatures 1 and 2 disclose a toner supplying apparatus that can considerably alleviate the problem in the conventional image forming apparatus. The toner supplying apparatus described in the Patent Literatures uses the suction force of a powder pump for the transfer of the toner. Therefore, there are advantages in that there is high flexibility in the arrangement of the toner container and toner can be supplied stably, thereby drawing much attention.
The toner container described in the Patent Literatures can be set in a setting unit in the image forming apparatus body with one action of dropping the container downward, at which time, the toner draining unit is automatically opened by a nozzle inserted in the container. When the toner container is taken out, the toner draining unit is automatically closed. This action is performed by a self-closing valve, and the self-closing valve includes a sponge in which a cross-shaped slit is formed at the center thereof. When the nozzle is inserted into the slit, the slit deforms so as to receive it, and when the nozzle is pulled out, the slit is closed due to the righting moment of the sponge to prevent the toner from spilling out of the container.
However, in the self-closing valve, the righting moment of the sponge may decrease due to curing at a low temperature, or due to a creep deformation with the lapse of time. When the righting moment decreases, the toner may leak and scatter until the slit of the self-closing valve closes, at the time of taking out the toner container.
A toner container resolving this problem is already proposed by the present applicant, and the details are shown in FIG. 21.
In a toner container 520 shown in FIG. 21, an inner shutter 560 is provided as a stopper, instead of the self-closing valve, and the inner shutter 560 includes a shutter member 561, a spring 562, a ring sealing member 563, and a spring bearing 564, and is provided in a cap member 523. The shutter member 561 is biased downward by a compression spring 562, to seal a toner draining port 524 in a state fitted to the ring sealing member 563, so that the toner does not leak outside.
As shown in FIG. 22, when the toner container 520 is set from above, a nozzle 551 is inserted while pushing the shutter member 561 upward, thereby releasing a toner drain passage.
When the toner container 520 is taken out after use, since the shutter member 561 returns to the original position in the state abutting against the nozzle 551, due to a biasing force of the spring 562, the toner leakage can be reliably prevented.
As images are formed repetitively by the image forming apparatus, the developer is consumed. Therefore, it is necessary to supply the developer by the consumed amount. For example, when the developing unit that visualizes the electrostatic latent image formed on a latent image carrier uses a two-component developer including the toner and the carrier, it is necessary to sequentially supply the toner by the consumed amount, since the toner is consumed with the image formation. Therefore, in the conventional image forming apparatus, a toner container storing the toner is provided, so as to supply the toner by the consumed amount from the toner container to the developing unit.
In the configuration in which the toner is supplied from the toner container, it is necessary to replace the empty toner container every time the toner in the toner container has been consumed. The replacement operation of the toner container is heretofore performed by a user in general.
In Patent Literature 3, a toner supplying apparatus is disclosed, in which in order to facilitate the replacement operation of the toner container by users, the toner container is set by dropping the toner container from above at the time of installation, and the toner container is lifted upward and detached at the time of detachment. In this apparatus, a self-closing valve is provided, which automatically opens only by dropping the toner container from above, and automatically closes only by lifting the toner container, in a toner draining unit, being a toner passage in the toner container. Further, the configuration thereof is simple such that a nozzle is provided in a setting unit of the image forming apparatus, and the self-closing valve provided in the toner container opens or closes by inserting or removing the nozzle.
FIG. 23 depicts a toner container 20 having a self-closing valve 201 disclosed in the Patent Literature 3. As the self-closing valve 201 of the toner container, one having a cross-shaped slit 201a for inserting or removing a nozzle made of a compressed foam sponge seal formed of a non-permeable material is used. The self-closing valve 201 formed of the sponge seal deforms so that when the point of the nozzle is pressed against the center of the cross-shaped slit 201a, the nozzle can be inserted, and when the nozzle is pulled out, the slit closes due to the righting moment of the sponge to prevent toner scattering caused by the toner spill.
Thus, by providing the self-closing valve in the toner draining unit in the toner container, the replacement operation of the toner container by the user is facilitated, and toner scattering at the time of replacement operation can be prevented to some extent.
(Patent Literature 1) Japanese Patent Application Laid-Open No. 2001-324863
(Patent Literature 2) Japanese Patent Application Laid-Open No. 2002-72649
(Patent Literature 3) Japanese Patent Application Laid-Open No. 2001-315851
However, the toner container 520 provided with the inner shutter 560 becomes an obstruction to toner discharge, since the inner shutter 560 is located above the nozzle 551 in the set state, and hence a toner bridge phenomenon in the container is likely to occur. The toner bridge in the upper part of the inner shutter 560 is hardly eliminated even by the air supplied for eliminating the toner bridge. As a result, the supply amount of the toner becomes unstable, and hence the residual amount of toner in the toner container may increase extremely.
In the self-closing valve in the Patent Literature 3, the righting moment of the sponge may decrease due to curing at a low temperature, or due to a creep deformation with the lapse of time, and when the righting moment decreases, a slight gap may be generated in the slit in the self-closing valve, at the time of taking out the toner container. When a gap is generated, in the conventional configuration in which the toner draining unit is facing the direction of gravity of the toner container, the toner may leak from the gap, drop and scatter.
When the nozzle is inserted into or pulled out from the toner container, even when the righting moment does not decrease in the material of the self-closing valve, a certain gap is generated between the self-closing valve and the nozzle. There is the possibility that the toner in the toner container leaks and scatters from this gap.
Recently, recycling of the parts constituting the container is considered for resource protection, instead of disposing the used toner container. However, with the conventional toner container, the sealing material formed of the elastic material is bonded to the body portion of the toner draining member (cap member) with an adhesive. Therefore, at the time of recycling the parts of the toner container, a complicated work for detaching the sealing material formed of the elastic material, bonded to the body portion of the toner draining member (cap member) becomes necessary, causing a problem in that recycling of the toner container is not easy.
This problem occurs likewise when a powder container for storing powder other than the toner is used.
With a view to the above problems, it is an object of the present invention to reduce toner leakage, which is likely to occur at the time of removing the toner container, without using the shutter means coming into the toner container.
It is another object of the present invention to reduce leakage of powder from a powder container at the time of setting or detaching the powder container.
It is still another object of the present invention to eliminate the shutter means coming into the toner container, to prevent a large amount of residual toner.
It is still another object of the present invention to provide a powder container, which makes recycling easy, a reproduction method thereof, a powder supplying unit, in which the powder container can be installed, and an image forming apparatus.